I think that underdrive for a super short build would be cool, but adding that kind of cost onto an Atlas... In front of a NP241 or NP231, that might be interesting IMO, plus wouldn't it give a 2L option? I've been thinking about rebuilding my NP231 and adding 2L to it while it's out, because I'm just too busy to take on anything like even installing an Atlas for awhile plus I'd like to see what happens to my bank account if I don't just spend money constantly of 3 vehicles and a bunch of other toys.
I do think TJs are geared WAY too fast when you're off-road. I could certainly see the multiple speeds for really slowing one down, but IMO a crawl ratio of 60:1 or greater is kind of the minimum for 33s I like to see for a vehicle doing some off-road. I still go back and forth on getting a 4 speed, though I have no experience with 60+:1, but I could imagine it being useful occasionally.
I think I'll still probably get an Atlas II someday with 5:1. Though I think I'd normally drive around in Low in 3rd gear, but I'd still have the ability to be more delicate than the OEM 2.72 x 3.83 x 3.07, which is fine on a lot of trails, but I don't like doing most stuff that fast and don't like the burning clutch smell personally.